The present invention relates to a system for controlling track-bound vehicles at least some of which are equipped as guide vehicles having onboard computer systems, transmitting and receiving equipment and position-determining equipment and are capable of exchanging data messages with a fixed control station having a computer system.
U.S. Pat. No. 4,015,804 issued Apr. 5, 1977, assigned to the same assignee as the present application, whose disclosure is incorporated herein by reference discloses a hierarchically organized, demand-controlled vehicle control system in which a plurality of track-bound vehicles is controlled from individual operations control centers. The individual vehicles carry on-board control equipment which cyclically exchange data with the operations control center, their fixed control station.
U.S. Pat. No. 4,198,678, issued Apr. 15, 1980, assigned to the same assignee as the present application, whose disclosure is incorporated herein by reference, proposes to use for the on-board control equipment computer systems each consisting of two computers which compare the results created by them and thus detect processing errors.
Since a failure of one of these computers still results in a failure of a vehicle and, consequently, in section blocking, the same application also proposes to hold a standby computer or a pair of standby computers ready for use when a computer or the whole computer system has failed.
However, this solution is relatively expensive because up to 4 computers are needed. Also, considerable space is required for the on-board computer systems on the vehicles. These disadvantages remain even if, in order to eliminate the need for emergency braking, in the event of a failure of a computer, two complete two-computer systems are selected alternately from the fixed control station to process the data messages and control the propulsion and braking equipment, as proposed in U.S. Pat. No. 4,181,945, issued Jan. 1, 1980, assigned to the same assignee as the present application, whose disclosure is incorporated herein by reference.
Particularly the handling of crowds of people during the rush hours, which requires high system availability, necessitates the provision of a large number of vehicles equipped with two expensive two-computer systems each. During the remainder of the day, a large part of these vehicles remains unused.